1. Field of the Invention
The invention is directed to the field of tubular structures and principally to a uniquely formed crimpable ferrule having a principal use as a connector for electrical conductors and the like.
2. Description of the Prior Art
Prior art metallic ferrules for electrical connection or the like were generally formed from a length of electrically conductive seamless or joined tubing such as copper, aluminum, and other similar non-ferrous materials which were cut to the desired length to provide a crimpable sleeve for attachment to one or more conductors. Another process for forming such tubular sleeves entailed the manufacture of eyelet-like members stamped and drawn from flat stock, with the attendant production of a substantial amount of waste material as a consequence thereof. Due to the rapidly increasing cost of electrically conducting stock material there has been a great need for a low cost tubular ferrule for use in electrical connectors or the like which would be less expensive to manufacture than such prior art devices, yet would perform at least as well in use. A further disadvantage of such prior art devices was the expense and complexity associated with the addition thereto firstly, of internally directed insulation piercing means for piercing the outer covering of insulation or oxide coated wires about which the ferrule was to be crimped and, secondly, of external striations or teeth for gripping an overlying sleeve. In U.S. Pat. No. 3,390,227, issued June 25, 1968 to Shlesinger, Jr. and U.S. Pat. No. 3,333,047, issued July 25, 1967 to Geoffroi, there are disclosed connecting devices utilizing helically coiled wire to form a sleeve-like member. Such devices still failed to provide a suitable substitute for a solid wall tubular sleeve since the turns of wire utilized to form the coil are spaced from one another and, upon compression, provide only a small fraction of the contact area provided by the solid wall tubular sleeve. It should be further noted that such spaced turns will tend to further undesirably separate upon crimping, thereby unpredictiably affecting the integrity of the final joint.